This protocol evaluates the effects of a high (>200 meq/d) versus a low (<20 meq/d) sodium diet on the ability of insulin to promote glucose uptake during euglycemic clam conditions pursuing the hypothesis that a high salt intake suppresses both renin and sympathetic activity leading to a greater skeletal muscle blood flow and increased insulin sensitivity compared to the low salt diet which raises plasma free fatty acid (FFA) concentrations. We have incorporated studies using a stable isotope of glycerol to evaluate the role of these changes.